1. Field of the Invention
This invention relates to endoscopic surgical instruments. More particularly, this invention relates to an instrument for taking multiple biopsy tissue samples and which is provided with bipolar cautery capability.
2. State of the Art
Endoscopic biopsy procedures are typically performed with an endoscope and an endoscopic biopsy forceps device (bioptome). The endoscope is a long flexible tube carrying fiber optics and having a narrow lumen through which the bioptome is inserted. The bioptome typically includes a long flexible coil having a pair of opposed jaws at the distal end and manual actuation means at the proximal end. Manipulation of the actuation means opens and closes the jaws. During a biopsy tissue sampling operation, the surgeon guides the endoscope to the biopsy site while viewing the biopsy site through the fiber optics of the endoscope. The bioptome is inserted through the narrow lumen of the endoscope until the opposed jaws arrive at the biopsy site. While viewing the biopsy site through the fiber optics of the endoscope, the surgeon positions the jaws around a tissue to be sampled and manipulates the actuation means so that the jaws close around the tissue. A sample of the tissue is then cut and/or torn away from the biopsy site while it is trapped between the jaws of the bioptome. Keeping the jaws closed, the surgeon withdraws the bioptome from the endoscope and then opens the jaws to collect the biopsy tissue sample.
A biopsy tissue sampling procedure often requires the taking of several tissue samples either from the same or from different biopsy sites. Unfortunately, most bioptomes are limited to taking a single tissue sample, after which the device must be withdrawn from the endoscope and the tissue collected before the device can be used again to take a second tissue sample. The single-sample limitation of most bioptomes is due to the limited space between the biopsy forceps jaws. Several attempts have been made to provide an instrument which will allow the taking of several tissue samples before the instrument must be withdrawn and the samples collected. Problems in providing such an instrument include the extremely small size required by the narrow lumen of the endoscope and the fact that the instrument must be flexible in order to be inserted through the lumen of the endoscope.
Co-owned application Ser. No. 08/189,937 discloses an endoscopic multiple sample bioptome which includes a relatively long flexible member having a lumen with an axially displaceable wire extending therethrough. The proximal ends of the flexible member and wire are coupled to a manual actuation means for axially displacing one of the flexible member and wire relative to the other. The distal end of the flexible member is coupled to either a cylinder preferably having a knife sharp distal edge, or a jaw assembly. The distal end of the wire is coupled to the other of the cylinder and the jaw assembly. The jaw assembly includes a pair of opposed toothed jaw cups each of which is coupled by a narrow arm to a base member. The narrow arm of each jaw is preferably formed from Nitinol as described in U.S. Ser. Nos. 08/440,326 and 08/440,327 and is arranged to urge the jaws away from each other. The base member of the jaw assembly is mounted inside the cylinder and axial movement of one of the jaw assembly and cylinder relative to the other draws the necks of the jaws into the cylinder or moves the cylinder over the necks of the jaws to bring the jaw cups together in a biting action.
Clearly, where traumatic procedures such as taking a biopsy are being conducted, the ability to conduct endoscopic cautery procedures is desirable in order to stem bleeding. While both monopolar and bipolar endoscopic cautery instruments are known (such as disclosed in U.S. Pat. No. 4,418,692 to Guay), increasingly, bipolar cautery is preferred because it is less traumatic to the patient. In bipolar cautery instruments, the electric current path is from one electrode, through the tissue to be cauterized, and then through to the other electrode and out of the instrument. Thus, cauterization is limited to only that tissue between the two electrodes. On the other hand, in monopolar instruments, the patient effectively becomes the second electrode, and the cautery current is dissipated through the patient. In the monopolar situation, control of the cautery location is not exact, and tissue surrounding the tissue to be cauterized is also subject to different degrees of cautery.
In U.S. Pat. No. 4,763,660 to Jaeger, a bipolar endoscopic microelectrocautery device is shown. The Jaeger patent also discloses a device for obtaining biopsies. However, the device disclosed in Jaeger requires a number of different single function "instrument heads" only one of which may be attached at any time to the instrument for performing a specific function such as grasping, cutting, or cauterizing. Thus, the biopsy forceps "head", is incapable of cauterizing, while the cauterizing "head" is incapable of obtaining a biopsy. This arrangement does not permit the surgeon to cauterize at the biopsy site at the time of taking a biopsy.